1. Field of the Invention
The present invention generally relates to a plug connector used for balanced transmission, and particularly relates to a plug connector provided with substantially right-angled contact portions protruded backward from the housing.
2. Description of the Related Art
Recently, along with rapid improvement in personal computers and computer networks, there is a need for transmitting a large amount of data, particularly moving-image data. In order to transmit a large amount of moving-image data, a high-speed transmission of at least 1 gigabit/sec is required. However, an unbalanced transmission system is not suitable for such a high-speed transmission since it is easily affected by noise. Thus, for a high-speed transmission, a balanced transmission system is preferred since it is less affected by noise as compared to the unbalanced transmission system.
Plug connectors can be roughly divided into straight-type plug connectors and right-angled type plug connectors. A straight-type plug connector is provided with contact elements protruded vertically downward from the housing. A right-angled type plug connector is provided with substantially right-angled or L-shaped contact elements protruding backward from the housing and bent vertically downward. Since lengths of the contact elements are longer for the right-angled contact elements, there is a higher possibility of requiring an impedance matching for the right-angled type plug connectors.
Therefore, there is a need for a plug connector which can be used in a balanced transmission system and which has a structure taking into account an impedance matching of signal contacts.
In the related art, a right-angled type plug connector taking in account an impedance matching is known, which plug connector is provided with a bracket made of electrically insulating synthetic resin covering the substantially right-angled contact elements protruding backward from the housing.
However, with the plug connector of the related art, since the bracket is provided beneath the contact elements, upper sides of the contact elements are completely exposed to the air. Therefore, an impedance matching is not sufficiently implemented by changing a material used as the synthetic resin of the bracket.
Therefore, there is a need for a plug connector having substantially right-angled contact elements and used for balanced transmission, which plug connector can easily implement an impedance matching.
Accordingly, it is a general object of the present invention to provide a plug connector which can satisfy the needs described above.
It is another and more specific object of the present invention to provide a plug connector which can effectively implement an impedance matching between positive signals and negative signals.
In order to achieve the above object, a plug connector includes:
an electrically insulating body including a housing and a pair of arms;
a plurality of pairs of first and second right-angled signal contact elements supported by the housing such that the first right-angled signal contact element is arranged above the second right-angled signal contact element, each of the right-angled signal contact elements having a substantially right-angled contact portion protruding backward from the housing and a leading portion inserted into the housing, the contact portion having a horizontal part and a vertical part;
a plurality of ground contact elements supported by the housing and disposed alternately with the plurality of pairs of first and second right-angled signal contact elements, each of the ground contact elements provided with two ground terminals; and
upper and lower electrically insulating brackets assembled to the housing,
wherein the upper bracket covering the horizontal parts of the plurality of first signal contact elements, the lower bracket covering the horizontal parts of the plurality of second signal contact elements, and the lower bracket provided with holes into which the vertical parts of the first and second signal contact elements and the ground terminals are inserted.
In the plug connector described above, an impedance of the first signal contact element and an impedance of the second signal contact element can be altered by changing the materials used for the upper and lower brackets. Also, since the plurality of first and second signal contact elements and the plurality of ground contact elements are alternately disposed, the above-described plug connector has a strip-line structure.
It is still another object of the present invention to provide a strip-line structure for the right-angled contact portions.
In order to achieve the above object, each of the plurality of ground contact elements has an extension protruding backward from the housing and a leading portion to be inserted into the housing, the extension having a size covering a projection area of the right-angled contact portions of the pair of first and second right-angled signal contact elements, the extension having an upper half part and a lower half part.
It is yet another object of the invention to protect the first and second signal contact elements from external noise.
In order to achieve the above object, the plug connector further includes an upper shielding member and a lower shielding member,
the upper shielding member including a substantially L-shaped body part and upper shield terminals, the body part including a rectangular horizontal shielding plate part provided on an upper side of the housing and a rectangular vertical shielding plate part covering a backside of the upper bracket and a backside of the lower bracket, and
the lower shielding member including a shield plate part of a rectangular shape and lower shield terminals.